1. Field of the Invention
The present invention relates to an ink-jet printing method and apparatus. More specifically, the invention relates to an ink-jet printing apparatus and an ink-jet printing method for performing printing by ejecting an ink and a printing quality improving liquid for making a component in an ink insoluble or coagulated, to a medium to be printed.
The present invention is applicable for all of devices or apparatuses employing a paper, a cloth, a non-woven fabric, an OHP sheet, and so forth, and even a metal as a printing medium. In concrete, the present invention is applicable for an office appliance, such as a printer, a copy machine, a facsimile machine and so forth, an industrial production machine or so forth.
2. Description of the Prior Art
Ink-jet printing systems have advantages of low noise, low running cost, easiness of down-sizing and providing color printing capability for the apparatus, and so forth, and have been widely used in a printer, a copy machine and so forth.
However, when an image is printed on a printing medium, such as a plain paper and so forth by such apparatus using the ink jet printing system, it is possible that water resistance of the printed image is insufficient. Also, in case of printing of color image, it is somewhat difficult to achieve both of high density image which may not cause feathering and an image which may not cause bleeding between adjacent colors. Therefore, it is often impossible to obtain high quality color image with high image fastness.
As a method to improve water resistance of the image, an ink containing color agent which is provided with water resistive property, has been put into practical use. However, water resistance of the image is still insufficient in many case. Further, in principle, the ink containing a water resistive coloring agent is an ink which is difficult to dissolve in the water when once dried. Therefore, such ink can easily cause plugging of ink-ejection openings in an ink-jet head. Also, a construction of an apparatus for preventing plugging of ink can be complicated.
On the other hand, in the prior art, there are large number of technologies for improving fastness of a printed medium. For example, in Japanese Patent Application Laid-open No. 24486/1978, there is disclosed a technology for fixing a dye to the medium by laking the dye through post-treatment of the dyed product to increase fastness of the dye on the medium.
Japanese Patent Application Laid-open No. 43733/1979 discloses a method of the ink jet printing system for performing printing employing two or more components which may enhance film forming performance by mutually contacting at normal temperature or upon heating. By this, mutually contacting respective components on the printing medium may form a printing product with a film firmly fixed on a printing medium.
Also, in Japanese Patent Application Laid-open No. 150396/1980, a method for applying water-proofing agent forming a lake with a dye after printing with a water soluble ink by ink-jet system, is disclosed.
In Japanese Patent Application Laid-open No. 128862/1983, an ink-jet printing method for printing a printing ink and printing quality improving liquid in overlapping manner with preliminarily identifying a position of an image to be printed is disclosed. In the disclosed method, the image is precedingly printed with the printing quality improving liquid in advance of printing by the printing ink, the printing quality improving liquid is applied in overlapping manner on the printing ink printed in advance, and the ink is applied in overlapping manner on the printing quality improving liquid in advance, then, the printing quality improving liquid is applied over the printing ink in overlapping manner.
However, in application of printing quality improving liquid to improve printing quality of printing with a conventional printing ink, it is typical to separately process the printing medium before printing or to perform a separate process after printing.